The present invention relates to a microwave oven and, more particularly, to a variable cooking mode selector for controlling a magnetron output in a microwave oven.
A control system has been proposed, which intermittently enables a magnetron employed in a microwave oven for varying a mean output level in accordance with variations of a repetition rate of magnetron energization.
In a conventional control system of the prior art, a contactless switching system made of a semiconductor circuit, or a complicated cam mechanism is employed to perform the intermittent switching operation. However, either the contactless switching system or the cam mechanism of the prior art is so complicated that a simple control system is eagerly desired.
Accordingly, an object of the present invention is to provide a microwave oven, wherein a mean output level of a magnetron employed in the microwave oven is selectable at a desired value.
Another object of the present invention is to provide a variable cooking mode selector of a simple construction for varying a mean output level of a magnetron employed in a microwave oven.
Still another object of the present invention is to provide a switching assembly of a simple construction for intermittently energizing a magnetron employed in a microwave oven.
Yet another object of the present invention is to provide a menu drum associated with a variable cooking mode selector for indicating a selected cooking mode.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and apecific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, a control cam plate having a periphery divided into plural, for example, four sections of different radiuses is provided and is driven into rotation by a cam motor mounted on a supporting table. The supporting table is disposed in a microwave oven housing in such a manner as to rotate about a middle portion thereof. One end of the supporting table is fixed to a manually operable selection lever, and the cam motor is mounted on the other end portion of the supporting table, whereby the control cam plate location is shifted in response to slide operation of the manually operable selection lever.
A switching means is associated with the control cam plate for intermittently energizing a magnetron employed in the microwave oven in response to the rotation of the control cam plate. The repetition rate of the magnetron energization is controlled by shifting the control cam plate through the manually operable selection lever, whereby a mean output level of the magnetron is varied.
In a preferred form, a menu drum is provided in such a manner as to rotate in response to the slide operation of the manually operable selection lever. The menu drum has four side walls on which menus suited for a selected cooking mode, for example, a full power mode, a roast mode, a simmer mode and a defrost mode are indicated.